Medical device probe and connector

ABSTRACT

A sensor probe has a connector and the connector&#39;s corresponding receptacle on a console have security mechanisms that ensure that the connector and the receptacle are properly connected and mated. The connector and receptacle can have physical security features that block insertion of the connector into the receptacle if they are not aligned in a proper orientation. The console can also include a software security feature that allows optical measurements from the sensor probe only if the connector of the sensor probe and receptacle on the console are connected properly. An adapter can also be used to convert a conventional receptacle mounted on a console into a receptacle with security features.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 15/445,656, filed Feb. 28, 2017, issued as U.S. Pat. No.10,357,190 on Jul. 23, 2019, which is a continuation of U.S. patentapplication Ser. No. 14/754,622, filed Jun. 29, 2015, issued as U.S.Pat. No. 9,579,051 on Feb. 28, 2017, which is a continuation of U.S.patent application Ser. No. 13/777,285, filed Feb. 26, 2013, issued asU.S. Pat. No. 9,066,692 on Jun. 30, 2015, which is a continuation ofU.S. patent application Ser. No. 12/477,611, filed Jun. 3, 2009, issuedas U.S. Pat. No. 8,382,666 on Feb. 26, 2013. These applications areincorporated by reference along with all other references cited in thisapplication.

BACKGROUND OF THE INVENTION

Connectors are an essential part of any device involving optical orelectrical communication. Connectors can be used to join lengths ofconductors (e.g., optical fibers or electrical wires) into longerlengths, or to provide optical or electrical connection of one device toanother. Generally, a connector must axially align a terminal end of anoptical fiber or electrical wire with a terminal end of another opticalfiber or electrical wire. It is important that there is no or minimalsignal transmission loss at the junction where two terminal ends of theoptical fibers or electrical wires are joined together inside theconnector.

In medical devices involving optical measurements, such as oximetrydevices, connectors are used to functionally connect a sensor probe to asystem unit or console which has components such as a display,processor, and other components. Optical fibers or electrical wires inthe sensor probe typically run uninterrupted from an oximeter sensor atthe distal end of the sensor probe, through a cable, to a connector. Theconnector physically and functionally connects the sensor probe to areceptacle mounted on the console. The connector axially aligns andconnects the ends of optical fibers (or electrical wires) from thesensor probe with their counterparts in the receptacle.

It is important that the connector properly aligns terminal ends ofconductors with their counterparts in the receptacle on the console sothat signal transmission is optimized. Furthermore, it is desired thatthe connector of a sensor probe is simple to use. Typically, a sensorprobe for an oximetry device is disposed after a single use. Thus, amedical professional needs to attach and detach sensor probes to aconsole after each use. It is desired that proper connection between aconnector of a sensor probe and a receptacle on a console is intuitiveand easy for the medical professional so that no inadvertent mistake ismade during the connection.

Embodiments of the invention meet this and other needs.

BRIEF SUMMARY OF THE INVENTION

A connector of a sensor probe and its receptacle mounted on a console(which is configured to mate with the connector of the sensor probe)have security mechanisms that ensure proper connection between theconnector and the receptacle. The security mechanisms include a hardwarefeature. For example, a blocking cylinder present in the receptacleprohibits the connector of the sensor probe to be inserted if it is notproperly aligned with the receptacle. The security mechanism alsoincludes a software feature where the console prohibits opticalmeasurements by the sensor probe if the connector of the sensor probe isnot inserted into the receptacle on the console in a specificorientation.

In one aspect of the invention, the connector of the sensor probe has ahousing that includes a first end portion, a second end portion on theopposite side of the first end portion. The housing of the connectoralso has a first end face at the first end portion and a second end faceat the second end portion, where the first and second end faces aregenerally parallel to each other. The housing of the connector alsoincludes a number of apertures which extend along a longitudinal axis ofthe connector from the first end face to the second end face. Some ofthe apertures are filled with conductors, such as optical fibers,electrical wires, or both. Among the apertures, a top portion of oneaperture has a diameter larger than other apertures, and it isconfigured to receive a blocking cylinder head of a receptacle on aconsole.

In another aspect of the invention, the receptacle on a console includesa distal end portion which is configured to mate with the connector ofthe sensor probe. The receptacle includes a proximal end portion on theopposite side of a distal end portion, where the proximal end portion isconfigured to be affixed to a console. The receptacle also includes adistal end face at the distal end portion and a proximal end face at theproximal end portion, where the distal and proximal end faces aregenerally parallel to each other.

The receptacle also has a number of apertures along a longitudinal axisof the receptacle between the distal end face and the proximal end face,where the apertures are to be aligned with their counterpart aperturesin the connector. Some of the apertures are filled with optical fibers,electrical wires, or both. The receptacle also includes a blockingcylinder having a head portion that has a larger diameter than a tailportion of the blocking cylinder. The tail portion of the blockingcylinder is inserted into one aperture, and the head portion of theblocking cylinder protrudes from the aperture at the distal end face.

The head portion of the blocking cylinder is configured to fit into oneof apertures in the connector of the sensor probe. If the blockingcylinder is not properly inserted into the cylinder receiving aperturein the connector of the sensor probe, the connector of the sensor probecannot be properly connected to the receptacle on the console.Furthermore, an identifier circuit in the console will prohibit anyoptical measurements from the sensor probe when the blocking cylinderhead of the receptacle is not fully inserted into an aperture in theconnector of the sensor probe.

In yet another aspect of the invention, a sensor probe includes anoximeter sensor comprising a first source structure and a first detectorstructure, a connector, and a cable that joins the oximeter sensor tothe connector. The cable includes conductors (e.g., optical fibers,electrical wires, or both), and distal ends of the conductors areconnected to the first source structure and the first detector structureof the oximeter sensor and proximal ends of the conductors are insertedand connected to apertures in the connector.

In yet another aspect of the invention, a tissue retractor sensor probeincludes a retractor for retracting a tissue, where the retractor has ashaft, a handle coupled to a proximal end of the shaft, and a tipcoupled to a distal end of the shaft. The tip of the tissue retractorsensor probe includes a retractor portion and an oximeter sensor. Thetissue retractor sensor probe also includes a cable which connects theoximeter sensor probe to a connector, which is used to functionallyconnect the tissue retractor sensor probe to its receptacle on theconsole.

In yet another aspect of the invention, an adapter can convert aconventional receptacle without a blocking cylinder to a new receptaclewith a blocking cylinder so that it is configured to receive a connectorof a sensor probe in accordance with the present invention. The adaptercan include a receptacle member and a connector member which areenclosed in a single housing. Alternatively, the receptacle member andthe connector member of the adapter are connected by a cable.

In yet another aspect of the invention, a method includes determiningwhether there is a conduction path between a blocking cylinder in areceptacle on a console and a metal pin which is inserted in an apertureof a connector of a sensor probe, prior to making any tissue oxygensaturation measurements.

Other objects, features, and advantages of the present invention willbecome apparent upon consideration of the following detailed descriptionand the accompanying drawings, in which like reference designationsrepresent like features throughout the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of an oximeter system for measuring oxygensaturation of tissue in a patient.

FIG. 2 shows a more detailed block diagram of a specific implementationof the system of FIG. 1.

FIG. 3 shows a system of the invention including a monitoring consolewith a receptacle and a small patch sensor probe, where the small patchsensor probe includes an oximeter sensor, cable, and connector.

FIG. 4A shows a cross-sectional view of a connector of a sensor probe.

FIG. 4B shows a longitudinal sectional view of the connector shown inFIG. 4A when the connector is sliced along a line connecting between twoA's.

FIG. 5A shows a cross-sectional view of a receptacle on a console.

FIG. 5B shows a longitudinal sectional view of the receptacle shown inFIG. 5A when the receptacle is sliced along a line connecting betweentwo B's.

FIG. 5C shows a longitudinal sectional view of a connector of a sensorprobe which is fully inserted and connected to its receptacle on aconsole.

FIG. 5D shows a longitudinal sectional view of a connector of a sensorprobe which is incompletely inserted and improperly connected to itsreceptacle on a console.

FIG. 6A shows a sensor probe where a connector at its distal end isseparated from the rest of the sensor probe to show internal componentsof the sensor probe.

FIG. 6B shows a longitudinal sectional view of a connector of a sensorprobe with a metal pin and an optical fiber in apertures of theconnector.

FIG. 6C shows a cross-sectional view of a receptacle on a console.

FIG. 7A shows a cross-sectional view of another implementation of aconnector of a sensor probe, where two apertures of the connector arefilled with conductors.

FIG. 7B shows a cross-sectional view of a receptacle which receives theconnector shown in FIG. 7A.

FIG. 8A shows a cross-sectional view of yet another implementation of aconnector of a sensor probe, where four apertures of the connector arefilled with conductors.

FIG. 8B shows a cross-sectional view of a receptacle which receives theconnector shown in FIG. 8A.

FIG. 9A shows a longitudinal sectional view of an adapter that includesa female connector member at one end of the adapter, and a malereceptacle member at the opposite end of the connector member.

FIG. 9B shows a longitudinal sectional view of another adapter thatincludes a female connector member at one end of the adapter, and a malereceptacle member at the opposite end of the connector member.

FIG. 10 shows a surgical elevator sensor probe.

FIG. 11 shows an implementation of a system which includes a monitoringconsole with a receptacle and a nerve retractor sensor probe with aconnector.

FIG. 12 shows a perspective view of a first implementation of a tip of anerve retractor sensor probe.

FIG. 13 shows a bottom view of the first implementation of a tip of anerve retractor sensor probe.

FIG. 14 shows a perspective view of a second implementation of a tip ofa nerve retractor sensor probe.

FIG. 15 shows a bottom view of the second implementation of a tip of anerve retractor sensor probe.

FIG. 16 shows a perspective view of a third implementation of a tip of anerve retractor sensor probe.

FIG. 17 shows a bottom view of the third implementation of a tip of anerve retractor sensor probe.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect of the invention, a connector of a sensor probe and itsreceptacle on a console (which is configured to receive and mate withthe connector of the sensor probe) have security mechanisms that ensureproper connection between the connector and the receptacle. In oneembodiment, the connector and receptacle have physical security featuresthat block insertion of the connector into the receptacle if they arenot aligned in a proper orientation. In another embodiment, the consoleincludes a software security feature that allows optical measurementsfrom the sensor probe only if the connector and receptacle are properlyconnected.

In another aspect of the invention, an adapter can be used to convert aconventional receptacle on a console into a receptacle with securityfeatures in accordance with the present invention. A new receptacleprovided by the adapter also makes it easier for the user to align andattach a sensor probe to the console. The new receptacle also minimizesa risk that the user may inadvertently insert the connector of thesensor probe into its receptacle on the console in a wrong orientation,which can potentially damage components in the sensor probe or console.

In yet another aspect of the invention, an adapter can be provided witha cable which lengthens the connection between a console and a sensorprobe. The adapter with a cable is useful in situations when a surgicalsetting requires a patient to be kept at a distance from the consolebecause of potential contamination issues.

The connector and receptacle assemblies can include optical fibers orfiber optic bundles for optical transmission, electrical wires forelectrical transmission, or both. In this application, optical fibers,fiber optic bundles, or electrical wires are collectively referred to asconductors.

Examples of embodiments of the invention are illustrated using figuresand are described below. The figures described herein are used toillustrate embodiments of the invention, and are not in any way intendedto be restrictive of the broad invention. Embodiments of the inventionare not limited to the specific arrangements and constructions shown anddescribed. For example, features shown in one figure can be combinedwith features shown in another figure.

FIG. 1 shows an oximeter system 101 for measuring oxygen saturation of atissue in a patient. The system includes a system unit 105 and a sensorprobe 108, which is connected to the system unit via a wired connection112. Connection 112 may be an electrical, optical, or another wiredconnection including any number of wires (e.g., one, two, three, four,five, six, or more wires or optical fibers), or any combination of theseor other types of connections. In other implementations of theinvention, however, connection 112 may be wireless such as via a radiofrequency (RF) or infrared communication.

Typically, the system is used by placing the sensor probe in contact orclose proximity to tissue (e.g., nerve or skin) at a site where oxygensaturation or other related measurement is desired. The system unitcauses an input signal to be emitted by the sensor probe into the tissue(e.g., human tissue). There may be multiple input signals, and thesesignals may have varying or different wavelengths. The input signal istransmitted into or through the tissue.

Then, after transmission through or reflection off the tissue, thesignal is received at the sensor probe. This received signal is receivedand analyzed by the system unit. Based on the received signal, thesystem unit determines the oxygen saturation of the tissue and displaysa value on a display of the system unit.

In an implementation, the system is a tissue oximeter, which can measureoxygen saturation without requiring a pulse or heart beat. A tissueoximeter of the invention is applicable to many areas of medicine andsurgery including plastic surgery and spinal surgery. The tissueoximeter can make oxygen saturation measurements of tissue where thereis no pulse; such tissue, for example, may have been separated from thebody (e.g., a flap) and will be transplanted to another place in thebody.

Aspects of the invention are also applicable to a pulse oximeter. Incontrast to a tissue oximeter, a pulse oximeter requires a pulse inorder to function. A pulse oximeter typically measures the absorbance oflight due to the pulsing arterial blood.

There are various implementations of systems and techniques formeasuring oxygen saturation such as discussed in U.S. Pat. Nos.6,516,209, 6,587,703, 6,597,931, 6,735,458, 6,801,648, and 7,247,142,7,355,688, and 7,525,647. These patents are assigned to the sameassignee as this patent application and are incorporated by referencealong with all other references cited in this application.

FIG. 2 shows greater detail of a specific implementation of the systemof FIG. 1. The system includes a processor 204, display 207, speaker209, signal emitter 231, signal detector 233, volatile memory 212,nonvolatile memory 215, human interface device or HID 219, I/O interface222, and network interface 226. These components are housed within asystem unit enclosure. Different implementations of the system mayinclude any number of the components described, in any combination orconfiguration, and may also include other components not shown.

The components are linked together using a bus 203, which represents thesystem bus architecture of the system. Although this figure shows onebus that connects to each component, the busing is illustrative of anyinterconnection scheme serving to link the subsystems. For example,speaker 209 could be connected to the other subsystems through a port orhave an internal direct connection to processor 204.

A sensor probe 246 of the system includes a probe 238 and connector 236.The probe is connected to the connector using wires 242 and 244. Theconnector removably connects the probe and its wires to the signalemitter and signal detectors in the system unit. There is one cable orset of cables 242 to connect to the signal emitter, and one cable or setof cables 244 to connect to the signal detector. In an implementationthe cables are fiber optic cables, but in other implementations, thecables are electrical wires.

Signal emitter 231 is a light source that emits light at one or morespecific wavelengths. In a specific implementation, two wavelengths oflight (e.g., 690 nanometers and 830 nanometers) are used. In otherimplementations, other wavelengths of light may be used. The signalemitter is typically implemented using a laser diode or light emittingdiode (LED). Signal detector 233 is typically a photodetector capable ofdetecting the light at the wavelengths produced by the signal emitter.

Connector 236 may have a locking feature; e.g., insert connector, andthen twist or screw to lock. If so, the connector is more securely heldto the system unit and it will need to be unlocked before it can beremoved. This will help prevent accidental removal of the probe.

The connector may also have a first keying feature, so that theconnector can only be inserted into a connector receptacle of the systemunit in one or more specific orientations. This will ensure that properconnections are made.

The connector may also have a second keying feature that provides anindication to the system unit which type of probe is attached. Thesystem unit may handle making measurements for a number of differenttypes of probes. When a probe is inserted, the system uses the secondkeying feature to determine which type of probe is connected to thesystem. Then the system can perform the appropriate functions, use theproper algorithms, or otherwise make adjustments in its operation forthe specific probe type.

For example, when the system detects a cerebral probe is connected, thesystem uses cerebral probe algorithms and operation. When the systemdetects that a thenar probe is connected, the system uses thenar probealgorithms and operation. When the system detects that a nerve retractorsensor probe is connected, the system uses nerve retractor probealgorithms and operation. A system can handle any number of differenttypes of probes. There may be different probes for measuring differentparts of the body, or different sizes or versions of a probe formeasuring a part of the body (e.g., three different thenar probemodels).

With the second keying feature, the system will be able to distinguishbetween the different probes. The second keying feature can use any typeof coding system to represent each probe including binary coding. Forexample, for a probe, there are four second keying inputs, each of whichcan be a logic 0 or 1. With four second keying inputs, the system willbe able to distinguish between sixteen different probes.

Probe 246 may be a handheld tool and a user moves the probe from onepoint to another to make measurements. However, in some applications,probe 246 is part of an endoscopic instrument or robotic instrument, orboth. For example, the probe is moved or operated using a guidinginterface, which may or may not include haptic technology.

In various implementations, the system is powered using a wall outlet orbattery powered, or both. Block 251 shows a power block of the systemhaving both AC and battery power options. In an implementation, thesystem includes an AC-DC converter 253. The converter takes AC powerfrom a wall socket, converts AC power to DC power, and the DC output isconnected to the components of the system needing power (indicated by anarrow 254). In an implementation, the system is battery operated. The DCoutput of a battery 256 is connected to the components of the systemneeding power (indicated by an arrow 257). The battery is rechargedusing a recharger circuit 259, which received DC power from an AC-DCconverter. The AC-DC converter and recharger circuit may be combinedinto a single circuit.

The nonvolatile memory may include mass disk drives, floppy disks,magnetic disks, optical disks, magneto-optical disks, fixed disks, harddisks, CD-ROMs, recordable CDs, DVDs, recordable DVDs (e.g., DVD-R,DVD+R, DVD-RW, DVD+RW, HD-DVD, or Blu-ray Disc), flash and othernonvolatile solid-state storage (e.g., USB flash drive),battery-backed-up volatile memory, tape storage, reader, and othersimilar media, and combinations of these.

The processor may include multiple processors or a multicore processor,which may permit parallel processing of information. Further, the systemmay also be part of a distributed environment. In a distributedenvironment, individual systems are connected to a network and areavailable to lend resources to another system in the network as needed.For example, a single system unit may be used to collect results fromnumerous sensor probes at different locations.

Aspects of the invention may include software executable code orfirmware (e.g., code stored in a read only memory or ROM chip). Thesoftware executable code or firmware may embody algorithms used inmaking oxygen saturation measurements of the tissue. The softwareexecutable code or firmware may include code to implement a userinterface by which a user uses the system, displays results on thedisplay, and selects or specifies parameters that affect the operationof the system.

Further, a computer-implemented or computer-executable version of theinvention may be embodied using, stored on, or associated with acomputer-readable medium. A computer-readable medium may include anymedium that participates in providing instructions to one or moreprocessors for execution. Such a medium may take many forms including,but not limited to, nonvolatile, volatile, and transmission media.Nonvolatile media includes, for example, flash memory, or optical ormagnetic disks. Volatile media includes static or dynamic memory, suchas cache memory or RAM. Transmission media includes coaxial cables,copper wire, fiber optic lines, and wires arranged in a bus.Transmission media can also take the form of electromagnetic, radiofrequency, acoustic, or light waves, such as those generated duringradio wave and infrared data communications.

For example, a binary, machine-executable version, of the software ofthe present invention may be stored or reside in RAM or cache memory, oron a mass storage device. Source code of the software of the presentinvention may also be stored or reside on a mass storage device (e.g.,hard disk, magnetic disk, tape, or CD-ROM). As a further example, codeof the invention may be transmitted via wires, radio waves, or through anetwork such as the Internet. Firmware may be stored in a ROM of thesystem.

Computer software products may be written in any of various suitableprogramming languages, such as C, C++, C#, Pascal, Fortran, Perl, Matlab(from MathWorks, www.mathworks.com), SAS, SPSS, JavaScript, AJAX, andJava. The computer software product may be an independent applicationwith data input and data display modules. Alternatively, the computersoftware products may be classes that may be instantiated as distributedobjects. The computer software products may also be component softwaresuch as Java Beans (from Sun Microsystems) or Enterprise Java Beans (EJBfrom Sun Microsystems).

An operating system for the system may be one of the Microsoft Windows®family of operating systems (e.g., Windows 95, 98, Me, Windows NT,Windows 2000, Windows XP, Windows XP x64 Edition, Windows Vista, WindowsCE, Windows Mobile), Linux, HP-UX, UNIX, Sun OS, Solaris, Mac OS X,Alpha OS, AIX, IRIX32, or IRIX64. Microsoft Windows is a trademark ofMicrosoft Corporation. Other operating systems may be used, includingcustom and proprietary operating systems.

Furthermore, the system may be connected to a network and may interfaceto other systems using this network. The network may be an intranet,internet, or the Internet, among others. The network may be a wirednetwork (e.g., using copper), telephone network, packet network, anoptical network (e.g., using optical fiber), or a wireless network, orany combination of these. For example, data and other information may bepassed between the computer and components (or steps) of a system of theinvention using a wireless network using a protocol such as Wi-Fi (IEEEstandards 802.11, 802.11a, 802.11b, 802.11e, 802.11g, 802.11i, and802.11n, just to name a few examples). For example, signals from asystem may be transferred, at least in part, wirelessly to components orother systems or computers.

In an embodiment, through a Web browser or other interface executing ona computer workstation system or other device (e.g., laptop computer,smartphone, or personal digital assistant), a user accesses a system ofthe invention through a network such as the Internet. The user will beable to see the data being gathered by the machine. Access may bethrough the World Wide Web (WWW). The Web browser is used to downloadWeb pages or other content in various formats including HTML, XML, text,PDF, and postscript, and may be used to upload information to otherparts of the system. The Web browser may use uniform resourceidentifiers (URLs) to identify resources on the Web and hypertexttransfer protocol (HTTP) in transferring files on the Web.

FIG. 3 shows one implementation of a system 300 which includes amonitoring console 303 and a sensor probe 305. Sensor probe 305 includesan oximeter sensor or oximeter sensor unit 310, a cable 315, and aconnector 320, where one end of the cable is connected to the probe andthe other end of the cable is connected to the connector. Connector 320is removably attached to a receptacle 325 which is affixed to or mountedon the monitoring console. For example, the receptacle can be mountedonto the console housing by a set of screws. The connector andreceptacle have security features which assist the user in connectingthem together in a correct orientation and in mated condition.

Oximeter sensor unit 310 measures oxygen saturation of a tissue. Eachoximeter sensor unit includes at least one source structure and at leastone detector structure. A source structure is a structure in theoximeter sensor unit that provides light that can be transmitted into atissue. The source structure can generate light, or it can be astructural component that transmits light generated elsewhere (e.g.,from an upstream source). A detector structure is a structure in theoximeter sensor unit that detects light (or that is a structuralcomponent of the detection process) which is scattered and reflectedfrom the tissue.

In the implementation shown in FIG. 3, oximeter sensor unit 310 includestwo source structures (S1 and S2) and four detector structures (D1, D2,D3, and D4) on its scanning surface that contacts a target tissue. Thesource structures and detector structures are shown as openings inoximeter sensor unit 310, and they may be referred to as openings orsensor openings in this application. The source structures and detectorstructures are physically and functionally connected to console 303 byconductors (e.g., optical fibers, electrical wires, or both) which runfrom the sensor unit to connector 320 inside the cable. The connector ofthe sensor probe aligns and couples the conductors with theircounterparts in the receptacle of the console.

In one embodiment, a source structure can be a laser or light emittingdiode (LED) that emits a light of a specific wavelength suitable tomonitor oxygen saturation. A detector structure can be a photodiode(e.g., a PN diode, a PIN diode, or an avalanche diode) that detects thelight transmitted and reflected from a tissue, after the sourcestructure emits the light into the tissue. In an oximeter sensor unit,both LEDs and photodiodes are located at the scanning surface of theoximeter sensor unit. These LEDs and photodiodes can then beelectrically connected to a system unit or console. In this embodiment,since the light is generated next to the tissue surface and subsequentlydetected at the tissue surface, there is less attenuation of a signal.

In another embodiment, a source structure is an opening in an oximetersensor unit (at its scanning surface) with an optical fiber inside,which is connected to an emitter located elsewhere (e.g., system unit).Likewise, a detector structure is an opening in an oximeter sensor unit(at its scanning surface) with an optical fiber inside, which isconnected to a detector located elsewhere. The optical fibers from eachoximeter sensor unit are then connected to either an emitter or adetector which may be located in a system unit or console.

In the latter embodiment, one or more optical fibers run along thelength of the cable, and distal ends of the optical fibers (or fiberoptic bundle) is inserted or attached to sensor openings. The proximalends of the optical fibers terminate inside connector 320. The proximalends of the optical fibers in the connector are aligned with theircorresponding optical fibers in the receptacle of the console, so thatlight generated in the console can be delivered to the oximeter sensorof a sensor probe.

While FIG. 3 illustrates an embodiment with six sensor openings in theoximeter sensor, any suitable number of sensor openings can be presentin the sensor probe. For example, there may be one, two, three, four,five, six, seven, or eight or more sensor openings. Any one or moresensor openings can be source structures, and any one or more sensoropenings can be detector structures. A number of source structures canbe equal to a number of detector structures in the oximeter sensor unit,or they can be different.

Further, oximeter sensor unit 310 shown in FIG. 3 has a particularsensor opening pattern where the arrangement of source structures anddetector structures are asymmetrical. The detector structures arealigned in a linear row and source structures are offset from eachother. In other words, a line drawn through the detector structures isnot parallel to a line drawn through the source structures.Additionally, the distance between openings D1 and D4 is shorter thanthe distance between openings S1 and S2.

In a specific implementation, a line drawn through openings D1 and S1 isperpendicular to a line drawn through openings D1 and D4. Also, a linedrawn through openings D1 and D4 is perpendicular to a line drawnthrough openings D4 and S2. Also, a distance between openings D1 and D4is five millimeters. A distance between each of the openings D1, D2, D3,and D4 is 5/3 millimeters. A distance between D1 and S2 is fivemillimeters. A diameter of an opening is one millimeter.

The selection of a number of sensor openings and sensor opening patternfor a sensor unit depends on many factors. For example, a small numberof sensor openings would require a relatively small scanning surface andthus a small sensor unit can be produced. A large number of sensoropenings may increase sensitivity of optical measurements. Furthermore,a larger separation between a source structure and a detector structuremay allow the detector structure to detect light after the light haspenetrated deeper into the tissue, compare to a sensor unit with asmaller separation between the two structures.

There are various other implementations of sensor opening patterns whichcan be incorporated into an oximeter sensor unit. Sensor openingpatterns can be either symmetrical or asymmetrical. Some of theseimplementations are discussed in U.S. Pat. No. 7,355,688, U.S. patentapplication Ser. No. 12/126,860, filed May 24, 2008, and U.S. patentapplication Ser. No. 12/178,359, filed Jul. 23, 2008. These patent andpatent applications are assigned to the same assignee as this patentapplication and are incorporated by reference. Any of the asymmetricalor symmetrical arrangements of sources and detectors discussed in thesepatent and patent applications are applicable to the source structuresand detector structures in this application.

In one implementation, console 303 (sometimes referred to as amonitoring console or system unit) shown in FIG. 3 can be a portableconsole which may be hand carried. A portable console can follow apatient and optical measurements can be made anywhere in the hospital.In this implementation, it is desirable that the portable console isbattery-operated. In another implementation, the console may be a large,nonportable device that is attached to a wall or secured to a stand. Inthis implementation, the system is typically connected to AC power.

The console may include a mass storage device to store data. Massstorage devices may include mass disk drives, floppy disks, magneticdisks, fixed disks, hard disks, CD-ROM and CD-RW drives, DVD-ROM andDVD-RW drives, flash and other nonvolatile solid-state storage drives,tape storage, reader, and other similar devices, and combinations ofthese.

The stored data may include patient information. This includes, forexample, the patient's name, social security number, or otheridentifying information, oxygen saturation measurements and the time anddate measured. The oxygen saturation measurements may include high, low,and average values and elapsed time between measurements.

The above drives may also be used to update software in the console. Theconsole may receive software updates via a communication network such asthe Internet.

In an implementation, the console also includes an interface fortransferring data to another device such as a computer. The interfacemay be a serial, parallel, universal serial bus (USB) port, RS-232 port,printer port, and the like. The interface may also be adapted forwireless transfer and download, such as an infrared port. The systemtransfers data without interruption in the monitoring of the patient.

The console also includes a display screen which may display thepatient's data, such as an oxygen saturation measurement. The screen maybe a flat panel display or include a touch screen interface so that theuser can input data into the console.

The console, in addition to the display, may also include a processor,signal emitter circuit, signal detector circuit, and a receptacle toremovably couple ends of one or more conductors. In a specificimplementation, the ends of one or more conductors (e.g., optical fibersor electrical wires) are instead permanently connected to the console.The signal emitter circuit may operate to send a signal through the oneor more conductors. The signal detector circuit then receives a signalvia one or more conductors.

In a specific implementation, the signal emitter circuit may include oneor more laser emitters, light emitting diode (LED) emitters, or both.The signal emitter circuit may be used to generate an optical signalhaving two or more different wavelengths to be transmitted through thesensor unit. The wavelengths may range from about 600 nanometers toabout 900 nanometers.

In a specific implementation, the console includes a first radiationsource and a second radiation source. The radiation sources may be dualwavelength light sources. In other words, first radiation sourceprovides two wavelengths of radiation and second radiation sourceprovides two wavelengths of radiation. First radiation source, secondradiation source, or both may include one or more laser diodes or lightemitting diodes (LEDs) that produce light in any wavelength, buttypically the wavelengths range from about 600 nanometers to about 900nanometers. In a specific implementation, a first wavelength of light isgenerated that has a wavelength of about 690 nanometers. A secondwavelength of light is generated that has a wavelength of about 830nanometers.

In a specific implementation, one or more near-infrared radiationsources are included within the console. In other implementations, theradiation sources may be external to the console. For example, theradiation sources may be contained within a separate unit between theconsole and sensor probe. The radiation sources may, for example, becontained in an oximeter sensor unit itself or in other parts (e.g., inthe handle of a tissue retractor sensor probe). In yet anotherimplementation, some radiation sources may be within the console whileother radiation sources are external to the console.

These radiation sources may be near-infrared lasers. In a specificimplementation, there is one near-infrared laser located within theconsole. In other implementations, there may be more than onenear-infrared laser. For example, there may be 2, 3, 4, 5, 6, 7, 8, 9,10 or more than 10 radiation sources. In another implementation, theradiation sources may include those that produce a visible light.

In one implementation, light emitted by different radiation sources isprovided to a beam combiner via optical fibers. The beam combinereffectively merges the light from different radiation sources, and themerged light is then provided via output optical fibers. The outputfibers are arranged to allow the merged or combined light to behomogenized to ensure that the light is substantially uniformlydistributed across the output fibers when the light enters the sensorunit. The beam combiner may be located in the console, or may be locatedoutside of the console.

In a specific implementation, a single pulse of light is transmittedinto the tissue. In another implementation, multiple pulses of light maybe transmitted into the tissue. For example, a first pulse of light maybe received by a first detector. A second pulse of light may be receivedby a second detector.

When light is transmitted to a target tissue via source structures inthe sensor unit, light scatters due to heterogeneous structure of thetissue, and some of the light is absorbed by chromophores such ashemoglobin. An attenuated version of the light that is reflected by thetissue is detected by detector structures in the sensor unit and istransmitted to the console. The oxygen saturation or hemoglobinconcentration of the tissue can be calculated based on a value of theinitial light generated by the signal emitter and a value of anattenuated version of the light that is reflected from the tissue and issubsequently detected by the signal detector.

In a specific implementation, an attenuation ratio is used to determinetissue oxygen saturation (StO₂), hemoglobin concentration (Hgb), orboth. Additional details on attenuation methods are also discussed inU.S. patent application Ser. No. 12/126,860, filed May 24, 2008, whichis incorporated by reference. The attenuation ratio method may alsoinclude techniques discussed in U.S. Pat. No. 6,587,701, which isincorporated by reference.

In the automatic error-cancellation or self-calibration scheme, thesystem factors such as source intensity, detector gain, and loss oflight in the optical fibers and connectors are cancelled automatically.The automatic error-cancellation scheme is discussed in more detail asequations 5a and 5b in U.S. Pat. No. 6,597,931, which is incorporated byreference. The self-calibration scheme may also include equationsdiscussed in U.S. Pat. Nos. 6,516,209, 6,735,458, and 6,078, 833, U.S.patent application Ser. No. 12/126,860, filed May 24, 2008, and NewOptical Probe Designs for Absolute (Self-Calibrating) NIR TissueHemoglobin Measurements, Proc. SPIE 3597, pages 618-631 (1999), whichare incorporated by reference.

In embodiments of the invention, the length of the cable may vary. In aspecific implementation, the length of the cable ranges from about 1.2meters to about 3 meters. For example, the cable may be about 1.3, 1.4,1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9,or 3.0 meters long or greater. Depending on the specific application,the cable length may be less than 1.2 meters. In some applications, thecable length will be greater than 3 meters. It may be desirable to uselonger cables when a patient is immune compromised and needs to be keptaway from sources of contamination, such as a console.

Connector 320 at the end of the cable attaches the sensor probe to itsreceptacle on the console. The connector also protects the cable fromaccidental disconnection. The connector may include a collar thatthreads onto the receptacle on the console. Alternatively, the connectormay include a lug closure, press-fit, or snap-fit components.

In a specific implementation, the console can provide alerts to the userwhen a proper connection is made between the sensor probe and theconsole. The alerts may be visual (e.g., a flashing light on a displayof console), audible, or both. The display monitor may also show a typeof sensor probe (e.g., small patch sensor probe, nerve retractor sensorprobe, and others) that is attached to the console, as well as otherinformation.

In a specific implementation, there may be other connectors on the cablebesides connector 320 and receptacle 325. These other connectors allowthe cable to be separated into two or more pieces, allow additionallengths of cable to be attached, or both.

These additional connectors provide several benefits. For example, thecable attached to the oximeter sensor can be disposed along with theoximeter sensor after use. The cables attached to the console can bereused. Thus, the cable more likely to be contaminated, i.e., the cableattached to the oximeter sensor, can be disposed. The cable less likelyto be contaminated, i.e., the cable attached to the console can bereused. As another example, the connectors may be used to attachadditional lengths of cable to extend the overall length of the cable.

In an implementation, the cable includes one or more optical wave guidesenclosed in a flexible cable jacket. The optical wave guides may be usedto transmit light from the console, through the oximeter sensor and outopenings in the oximeter sensor and into the tissue. The optical waveguides may also be used to transmit the light received from the tissueback to the console.

The optical wave guides may have the shape of a polygon, such as asquare, rectangle, triangle, or other shape. In other cases, the opticalwave guides may have circular or oval shapes. In a specificimplementation, the optical wave guides are multiple strands of fiberoptic cable. The flexible cable jacket may be thin-walled PVC with orwithout an aluminum helical monocoil, shrink wrap tubing, plastic,rubber, or vinyl.

In a specific embodiment, all of the fiber optic cables are enclosedwithin one end, or both ends of the flexible cable jacket. Minimizingthe number of exposed cables lowers the likelihood that the cables willget entangled. In another embodiment, the fiber optic cables are notenclosed together and instead each fiber optic cable is enclosed in itsown flexible cable jacket.

In a specific implementation, the cable is passive. For example, it willnot contain any active, generative properties to maintain signalintegrity. However, in other implementations, the cable may includeactive components. The cable may include active components to amplifythe signal transmitted through the sensor unit, received at the sensorunit, or both. For example, long lengths of cable subject to significantattenuation may require amplification. Amplification may also berequired if the monitored site contains a particularly dense structuresuch as bone. In a specific implementation, radiation sources such aslight emitting diodes (LEDs) may be placed in the sensor unit. Thus, thecable may contain electrical wiring to transmit power to the radiationsources.

In an embodiment of the invention, each opening on the sensor unit andcorresponding cable is dedicated to a particular purpose. For example, afirst opening on the sensor unit (and corresponding fiber optic cable)is dedicated to transmitting light from the monitoring console. A secondopening on the sensor unit is dedicated to transmitting a signalreceived at the second opening to the monitoring console.

Some embodiments use a particular opening and cable for multiplepurposes (e.g., both input and output) using a scheme such asmultiplexing.

In a specific embodiment, a particular opening and cable transmits anoutput to affect a reaction (e.g., sending electrical signals tostimulate muscle or other tissue). Another opening and cable transmitsthe resultant signal back to the monitoring device. In yet anotherembodiment, the openings and cables may simply detect changes andtransmit these changes back to the monitoring device. For example, theopenings and cables may carry voltage changes in the patient's skin backto the monitoring device.

In an implementation, the connectors on the cable, monitoring console,probe, and combinations of these have indicators. The indicators may becolor indicators that are painted on, or raised indicators, or both.These indicators help the user to properly attach the cable to themonitoring console, probe, or both. For example, the indicators mayinclude green arrows placed on the cable connectors, monitoring console,and probe. Alignment of the arrows indicates proper attachment of thecables. Further, there may be instructions printed on the console,cable, and probe oximeter that instruct the user on the properattachment of the cable.

FIG. 4A illustrates a cross-sectional view of one embodiment of aconnector 400 of a sensor probe when the connector is viewed from theconsole side. In other words, FIG. 4A is a view that the user will seewhen the user looks into an end face of the connector. FIG. 4B shows alongitudinal sectional view of the connector shown in FIG. 4A.

FIG. 5A shows a cross-sectional view of a receptacle 500 on a consolewhich is configured to receive the connector shown in FIG. 4A. Thereceptacle view shown in FIG. 5A is a view that the user will see whenthe user looks into the receptacle from outside of the console. FIG. 5Bshows a longitudinal sectional view of the receptacle shown in FIG. 5A.

As shown in FIG. 4A, the connector of a sensor probe has a housing 455that has fourteen apertures (numbered 1 through 14) which are generallyparallel to one another and extend along the longitudinal axis of thehousing. The apertures are arranged in four rows—a first row havingthree apertures; a second row having four apertures that are offset fromthe apertures of the first row; a third row having four apertures thatare aligned with the apertures of the second row; and a fourth rowhaving three apertures that are offset from the apertures of the thirdrow but are aligned with the apertures of the first row.

Among the fourteen apertures shown in FIG. 4A, aperture number 2, 3, 7,11, 13, and 14 are filled with conductors (e.g., optical fibers orelectrical wires). Other aperture can be empty, or may include featuresthat serve special functions, such as assisting in alignment of theconnector with the receptacle on the console. For example, aperturenumbers 6 and 9 represented by double concentric circles have metal pinswhich assist the console to determine what type of sensor probe isattached to the console, which will be described more in detail belowalong with FIGS. 6A through 6C.

FIG. 4B shows a longitudinal sectional view of connector 400 when theconnector is sliced along a line connecting two A's, across aperturenumbers 4 through 7 shown in FIG. 4A. As shown in FIG. 4B, the housinghas an internal cavity 463 at a first end portion 460 of the housing,and a first end face 461 which is recessed inside the internal cavity.There are also four passageways or apertures (numbers 4, 5, 6, and 7),where aperture number 7 is filled with a conductor 442. As shown in FIG.4B, a terminal end of conductor 442 may protrude from the first endface.

The connector further includes a collar 457 which is slidably mountedonto an outer surface of the housing of the connector. The remainingportion of the collar can be separated from the housing of theconnector, providing a groove 458 between the housing and the collar. Anend portion of the receptacle can be inserted into groove 458 of theconnector, and the collar can assist securing the connector to thereceptacle mounted on the console. The collar can have multiple ridges459 around its outer surface to assist the user to have a better griparound the collar when it is secured onto the receptacle.

FIG. 5A shows a cross-sectional view of one embodiment of a receptacle500 which is configured to receive the connector of the sensor probeshown in FIG. 4A. The receptacle is typically affixed, attached, ormounted on a housing of the console. The receptacle contains terminalends of conductors (e.g., optical fibers, electrical wires, or both)which are configured to align and couple with their counterparts in theconnector of a sensor probe. The conductors have first terminal ends inthe receptacle and their second terminal ends are connected to variouscomponents in the console (e.g., photodetector, radiation sources, andothers).

In FIG. 5A, the receptacle has a core member 510 which is surrounded bya sleeve member 520. The core member and the sleeve member are separatedby a concentric channel 525. When the connector on the sensor probe andthe receptacle on the console are brought together, housing 455 of theconnector is inserted into channel 525 of the receptacle, and sleevemember 520 of the receptacle is inserted into groove 458 of theconnector.

As shown in FIG. 5A, the receptacle also has fourteen apertures whichare to be aligned with apertures of the connector shown in FIG. 5A, whenthe connector and receptacle mate together. The fourteen apertures ofthe receptacle will align with their respective apertures in theconnector. For example, aperture number 1 of the receptacle will alignwith aperture number 1 of the connector; aperture number 2 of thereceptacle will align with aperture number 2 of the receptacle, and soforth. The corresponding pairs of apertures of the connector andreceptacle are shown as a mirror image of each other in FIGS. 4A and 5A.

In one implementation, a proximal end of a conductor 442 (e.g., opticalfiber) may extend beyond the first end face of the connector housing asshown in FIG. 4B. The protruded conductor is received by its counterpartaperture in a receptacle of a console. As shown in FIG. 5B, a terminalend of a conductor 542 in the receptacle is not flushed against the endsurface. Instead, the terminal end of conductor 542 is receded insidethe aperture, providing a gap for conductor 442 from the connector toenter into the aperture of the receptacle. By having conductors of theconnector insert themselves into the apertures of the receptacle of theconsole, light or signal transmission loss can be further minimized.

While the connector shown in FIG. 4A and the receptacle shown in FIG. 5Ahave fourteen apertures, they can include any suitable number ofapertures. For example, the connector and receptacle may include 10, 20,30, 40, 50, or any other number of apertures between these numbers.

The connector and the receptacle shown in FIGS. 4A through 5B haveseveral security features that ensure that they are connected in one orspecific orientations. The security features include both a hardwaremechanism (e.g., a physical block) and a software mechanism.

In one implementation, the connector and receptacle assembly hasphysical security features that block insertion of the connector intothe receptacle if they are not aligned in a proper orientation. As shownin FIGS. 5A and 5B, the receptacle has a blocking cylinder 531 inaperture number 4. The blocking cylinder has a shape of a steppedcylinder where its head or top portion has a diameter larger than abottom or tail portion of the cylinder. The tail portion of the cylinderfits into the aperture of the receptacle, whereas the head or topportion of the blocking cylinder (referred to as “blocking cylinderhead”) sits above the end face, outside of the aperture.

The blocking cylinder on the receptacle can be made of any suitablematerial, as long as it does not interfere with signal transmission. Forexample, the blocking cylinder may be made of a metal, plastic, ceramic,composite material, and others.

For the connector of the sensor probe shown in FIG. 4B, a top portion ofaperture number 4 near the internal cavity has a diameter larger thanthe remaining portion of aperture number 4 or other apertures. The topportion of aperture number 4 is configured to receive blocking cylinderhead 531 of the receptacle. This aperture is referred to as a “cylinderreceiving aperture” in this application. The user can align and insertthe blocking cylinder head of the receptacle into the cylinder receivingaperture (aperture number 4) of the connector. Because of a differencein aperture size, the user can readily recognize and align the cylinderreceiving aperture in the connector with the blocking cylinder head ofthe receptacle on the console.

The blocking cylinder head of the receptacle and the top portion of thecylinder receiving aperture of the connector have specific shapes andsizes so that the blocking cylinder head fits only into the top portionof the cylinder receiving aperture of the connector, but not into anyother apertures.

For example, the blocking cylinder head of the receptacle may have adiameter of about 4.5 millimeters, whereas the top portion of thecylinder receiving aperture of the connector has a diameter slightlylarger than 4.5 millimeters, such as between about 4.6 millimeters toabout 5.5 millimeters, more typically about 5.0 millimeters. Otherapertures in the connector (and also in the receptacle) and theremaining portion of the cylinder receiving aperture can have a diameterbetween about 2.0 millimeters to 4.0 millimeters, more typically about3.0 millimeters, so that the blocking cylinder head cannot be insertedinto these apertures.

The dimensions described above for the apertures and the blockingcylinder head are merely exemplary, and they can have any suitabledimensions as long as the top portion of the cylinder receiving apertureof the connector have a larger diameter to receive the blocking cylinderhead of the receptacle, and other apertures in the connector have adiameter too small to receive the blocking cylinder head. For example,other apertures (and also a bottom portion of the cylinder receivingaperture) in the connector can have a diameter which is between about 50to 80 percent, more typically about 60 percent, smaller than a diameterof a top portion of the cylinder receiving aperture.

The blocking cylinder head of the receptacle can also vary. For example,the blocking cylinder head can have a diameter of between about 4.0millimeters to 5.0 millimeters, whereas the cylinder receiving apertureof the connector can have a diameter slightly larger than the selecteddiameter of the blocking cylinder head.

Further, the blocking cylinder head may have a length between about 1millimeter to about 3 millimeters, whereas the tail portion of theblocking cylinder can have a length ranging between about 5 millimeterto about 15 millimeters. In a specific implementation, the head portionof the blocking cylinder has a length of about 2 millimeters, where asthe tail portion of the blocking cylinder has a length of about 10millimeters.

The top portion of the cylinder receiving aperture has a depth that hasthe same dimension or deeper than the length of the blocking cylinder.For example, if the blocking cylinder head has a length of 2millimeters, then the top portion of the cylinder receiving aperture hasa depth of about 3 millimeters. In a specific implementation, the topportion of the cylinder receiving aperture has a depth of about 2millimeters to about 5 millimeters.

While FIG. 4B shows that only the top portion of the cylinder receivingaperture has a larger diameter than other apertures, in someimplementation, the entire length of the cylinder receiving aperture mayhave a diameter larger than other apertures. Further, although theblocking cylinder and cylinder receiving aperture are located inaperture number 4 of the receptacle and connector, respectively, theycan be located at any other suitable apertures in the receptacle.

Further, although the use of a single blocking cylinder in a receptacleis illustrated, more than one blocking cylinder can be used inembodiments of the invention. For example, a receptacle may include two,three, four, or more blocking cylinders in different apertures, and aconnector may include a corresponding number of cylinder receivingapertures.

In a specific implementation, the blocking cylinder in the receptacleand the cylinder receiving aperture on the connector may be color codedto further assist the user. For example, the blocking cylinder on thereceptacle and the cylinder receiving aperture can be color matched(e.g., red, yellow, orange, green, and others) so that the user canreadily identify the two elements, and insert the blocking cylinder headof the receptacle into the colored aperture of the connector.

In another implementation, the connector and receptacle have additionalphysical security features that allow them to be connected in single orspecific orientations. For example, housing 455 of the connector hasmultiple keying nubs 456 which protrude from the outer surface of thehousing and which run longitudinally along the length of the housing.The multiple keying nubs on the housing may differ in size or may beunevenly spaced from one another.

An interior surface of the sleeve member of the receptacle has recessedregions 537 which are shaped so that they can receive keying nubs 456 ofthe connector. Since each keying nub of the connector and itscomplementary recessed region in the receptacle have unique shapes,typically one particular keying nub will fit into one particularrecessed region. Thus, the keying nubs of the connector and theircorresponding recessed regions in the receptacle assist the user injoining the connector and the receptacle in a proper orientation.

In yet another implementation, the connector of the sensor probe and itsreceptacle can have additional features which prevent accidentaldisconnection of the connector from the receptacle. In one embodiment,the collar of the connector can have helical threads around its innersurface and can act as a female screw member. The collar can radiallyrotate about a threaded end portion of the receptacle to secure theconnector of the sensor probe onto its receptacle on the console.

In another embodiment, the collar can have one or more latch elements447 (shown in FIG. 4A) molded integrally with collar in its innersurface for engaging latch recesses or slots on the receptacle (notshown in FIG. 5A). These and other features can prevent the user fromaccidentally disconnecting the connector of the sensor probe from thereceptacle.

In yet another implementation, the console can include a softwaresecurity feature that allows optical measurements from the sensor probeonly if the connector and the receptacle are properly connected. Forexample, the console can include an identifier circuit which candetermine whether or not the blocking cylinder head of the receptacle isproperly inserted into the cylinder receiving aperture of the connectorof the sensor probe. The identifier circuit can communicate with othercomponents in the console (e.g., signal emitter circuit) to initiatemeasurements of tissue oxygen saturation once it determines that aproper connection is made between the connector and the receptacle.

FIG. 5C illustrates an example where a connector 560 of a sensor probeis properly connected to its receptacle 580 on a console 590. A blockingcylinder head 581 is fully inserted into a cylinder receiving aperture561 of the connector. A metal pin 562 which is also inserted in anotheraperture of the connector. A terminal end 562 b of the metal pin isinserted into a corresponding aperture in the receptacle. A terminal end562 a of the metal pin and the blocking cylinder are electricallyconnected by a wire loop 563. The cylinder receiving aperture includes ametallic sleeve 565 which provides an electrical contact between theblocking cylinder head and the wire loop. Thus, the blocking cylinderand the metal pin are electrically connected on the connector side.

The blocking cylinder and the metal pin are also electrically connectedon the receptacle side. A tail portion of the blocking cylinder iselectrically connected to an identifier circuit 591 by a conductor 583.The terminal end of the metal pin is surrounded by a metallic sleeve564. The metallic sleeve is connected to the identifier circuit by aconductor 584, thereby providing an electrical connection between themetal pin and the identifier circuit.

As shown in FIG. 5C, when the blocking cylinder head of the receptacleis fully inserted into the cylinder receiving aperture of the connector,there is a closed circuit among the identifier circuit, blockingcylinder, and metal pin. The identifier circuit can transmit a signalthrough either conductor 583 or conductor 584 to determine if there is aclosed circuit.

In one implementation, wire loop 563 can be a low resistance metallicwire. In this implementation, the identifier circuit senses a shortcircuit conduction between the metal pin and the blocking cylinder. Theidentifier circuit can subsequently send a signal to a processor in theconsole to apply suitable algorithms to initiate tissue oxygensaturation measurements.

In another implementation, wire loop 563 can include a resistor having aspecific resistance value (e.g., 10-100 kiloohms). In thisimplementation, the identifier circuit can send a signal and determinewhether there is a conduction path between the blocking cylinder and themetal pin with a specified resistance value. Once the identifier circuitdetermines that there is a conduction path with a specified resistancevalue, the identifier circuit can transmit a signal to the processor inthe console to apply suitable algorithms to initiate oxygen saturationmeasurements.

FIG. 5D shows the same connector and receptor assembly as shown in FIG.5C, but they are not completely connected to each other. There may be asituation where the user inadvertently does not fully insert a connectorof a sensor probe into its receptacle on the console. As shown in FIG.5D, the blocking cylinder head of the receptacle has not been insertedinto the blocking cylinder receiving aperture of the connector. Thus,there is no conduction path between the blocking cylinder and the metalpin.

When the identifier circuit sends a signal through either conductor 583or 584 in FIG. 5D, the identifier circuit will determine that there isan open circuit. The identifier circuit can then send a signal to theprocessor in the console to prohibit any initiation of tissue oxygensaturation measurements. The identifier circuit can further send asignal to a display or speaker to alert the user that the connector ofthe sensor probe and its receptacle on the console are not properlyconnected.

Thus, by using both hardware features (e.g., a physical block by ablocking cylinder) and software features, the system not only providesan easy way to align the connector of the sensor probe and itsreceptacle on the console, the system also provides a safeguard againstmaking optical measurements when the sensor probe is not properlyconnected to the console.

In another aspect of the invention, FIG. 6A shows one implementation ofa sensor probe 600, where the sensor probe has a feature that allows theconsole to automatically determine which type of sensor probe isconnected to the receptacle on the console. There are different types ofsensor probes (e.g., a nerve retractor sensor probe, small patch sensorprobe, surgical elevator sensor probe, and others), and they usedifferent algorithms to measure tissue oxygen saturations. While thesystem may provide a user interface (e.g., keyboard, touchpad screen,voice activated input, and others) and the user can manually inputinformation, it may be desirable to have a system which automaticallyrecognizes a type of sensor probe that is inserted into the receptacleon the console.

As shown in FIG. 6A, sensor probe 600 includes an oximeter sensor 610, acable 615 which is connected to the oximeter sensor at one end and to acable end member 617 at the other end. The sensor probe also includes aconnector 620 which is connected to the cable end member. The cable endmember is configured so that it allows the cable to be joined toconnector 620. For example, the cable end member has threads in itsinner surface so that it can be threaded onto one end of the connector.The opposite end of the connector can then be removably attached to areceptacle affixed to a console (not shown in FIG. 6A).

The connector has a housing 655 which contains optical fibers and othercomponents. The connector also has a collar 631 which assists insecuring the connector of the sensor probe onto the receptacle mountedon the console.

As shown in FIG. 6A, cable end member 617 and connector 620 aredisconnected from each other so that components inside the sensor probecan be shown. There are optical fibers 626 which run continuously fromthe oximeter sensor down to the connector through the cable. Theconnector also includes a wire loop 629 which connects two metal pinsthat are inserted in apertures in the connector (not shown in FIG. 6A).As described below, the metal pins with a wire loop connection can beused by the console to distinguish which type of sensor probe isattached to the console.

FIG. 6B shows a longitudinal sectional view of connector 620 shown inFIG. 6A. The connector includes a housing 655 which holds optical fibersand other components. The housing of the connector includes a first endportion 631, a second end portion 633, a first end face 637 at the firstend portion, and a second end face 635 at the second end portion. Firstend face 637 is positioned inside an internal cavity 659 at the firstend portion of the housing. There are a number of apertures 641 whichextend from the first end surface to the second end surface of thehousing of the connector.

The connector also includes a collar 657 which is attached to thehousing at one end and can rotate about the housing and joins theconnector to the receptacle of the console. A groove 661 between thehousing and the collar of the connector provides space to receive asleeve member of a receptacle. The collar can be engaged onto a malecounterpart of the receptacle to provide a tight seal between the sensorprobe and the receptacle mounted on the console.

As shown in FIG. 6B, some of the apertures may be filled with opticalfibers 651. The optical fibers are typically protected by the use ofspring ferrules 653 in the connector. A ferrule is a component(typically a rigid tube) used to align and protect a stripped end of anoptical fiber. A ferrule is used together with a connector that connectsthe optical fiber to another optical fiber or to a device. The ferruleskeep the optical fibers accurately aligned within the connector.Ferrules can be made of glass, plastic, metal, or ceramic material. Theuse of spring ferrule in the connector reduces loss of light when lightpasses through the interface between the optical fiber in the connectorand the optical fiber in the receptacle of the console.

In one implementation, apertures in the connector may include metal pins643 as shown in FIG. 6B. Typically, two or more metal pins are insertedinto apertures in the housing of the connector. The metal pins areelectrically connected by wire loop 629 at the second end portion of theconnector as shown in FIG. 6A. The metal pins provide means for theconsole to automatically distinguish which type of sensor probe isconnected to the console, without any input from the user.

FIG. 6C shows a cross section of connector 620, viewed from the firstend portion of the housing of the connector. The cross section of theconnector shows a collar 657 and a housing 655. Inside the housing,there are fourteen apertures 641. Six out of fourteen apertures,aperture numbers 2, 3, 7, 11, 13, and 14, are filled with glass fiberbundles that lead to probe sensor openings S2, S1, D1, D3, D2, and D4,respectively.

Typically, the number of optical fibers or glass fiber bundles presentin the connector depends on the number of sensor openings that arepresent in the oximeter sensor unit. In some applications, a probe mayhave one, two, three, four, five, six, seven, eight, or more sensoropenings, and corresponding number of optical fibers. Some of theapertures in the connector may remain empty and unused (e.g., aperturenumber 1, 5, 8, 10, and 12) as shown in FIG. 6C.

In one implementation, the connector includes a feature that allows theconsole to determine which sensor probe is connected to the console. Forexample, different sensor probes can be designed to have differentelectrical properties at the connector. As shown in FIG. 6C, a sensorprobe of FIG. 6A can have aperture numbers 6 and 9 in the connectorfilled with metal pins (represented by a double circle) which areelectrically connected by a wire loop at the second end portion of theconnector housing.

When the connector of the sensor probe is properly inserted into itsreceptacle on the console, an identifier circuit in the console receivesa voltage or other signal from metal pins located at aperture numbers 6and 9. The wire loop connecting these two metal pins provides a shortcircuit or other form of conductive path between these two metal pins.The identifier circuit senses this short-circuit condition between themetal pins located in aperture numbers 6 and 9. The identifier circuitcan subsequently send a signal to a processor in the console. Based onthe aperture numbers that are involved in a short circuit, the processorcan determine which type of sensor probe is attached to the console.Then, the processor applies suitable algorithms and steps to makeoptical measurements from the sensor probe.

In one implementation, the identifier circuit shown in FIGS. 5C and 5Dcan also be used to determine which type of sensor probe is attached tothe console. Furthermore, one of the two metal pins in the connectorused to identify a type of sensor probe can be used to provide aconduction path for the blocking cylinder. For example, the metal pin inaperture number 9 shown in FIG. 6C can be used to identify that a smallpatch oximeter sensor unit is attached to the console (along with themetal pin in aperture number 6). The same metal pin in aperture number 9can be metal pin 562 shown in FIG. 5C which provides a conduction pathfor the blocking cylinder. Thus, one of the metal pins in the connectorcan serve a dual purpose.

When a different sensor probe is attached to the connector (e.g., anerve retractor sensor probe with two optical fibers), metal pins canoccupy different apertures in the connector. For example, for a nerveretractor sensor probe, the metal pins can be inserted into aperturenumbers 9 and 10. When the identifier circuit in the console determinesthat there is a short circuit condition between aperture numbers 9 and10, then it can send a signal to a processor that a nerve retractorsensor probe is attached to the console. By inserting the metal pinsinto different sets of apertures in the connector, the console canautomatically determine which sensor probe is connected to the console.

In embodiments of the invention, the connector and receptacle can bemade of any suitable materials. For example, the housing and collar ofthe connector and the core member and sleeve member of the receptaclecan be molded of plastic material (e.g., dielectric thermoplasticmaterial).

Furthermore, the connector and other components shown in FIGS. 6Athrough 6C can have any suitable dimensions. In a specificimplementation, when the cable end member and connector are tightlyscrewed together, they may have a combined length of about 80millimeters. Also, the diameter of the connector (including the collar)shown in FIG. 6C can be about 33 millimeters, and the diameter of thehousing of the connector can be about 20 millimeters.

While the connector and receptacle shown in FIGS. 4A, 5A, and 6C haveoval or elliptical cross sections, the connector and receptacle can haveany suitable shape. For example, they can have a circular cross section,rectangular cross section, square cross section, octagonal crosssections, and others.

FIGS. 7A, 7B, 8A, and 8B show variations of the connector and receptacleshown in FIGS. 4A through 5B, where both the connector and receptaclehave circular cross sections.

FIG. 7A shows a cross-sectional view of a connector 700 of anothersensor probe. In the embodiment shown in FIG. 7A, two apertures(aperture numbers 7 and 11) of the connector are filled with opticalfibers, rather than six apertures as shown in FIG. 4A. The connectorshown in FIG. 7A is typically used with a sensor probe with two sensoropenings in it oximeter sensor unit.

FIG. 7B shows a cross-sectional view of a receptacle 750 which isconfigured to mate with connector 700 of the sensor probe shown in FIG.7A. Receptacle 750 has six optical fibers in aperture numbers 2, 3, 7,11, 13, and 14. The receptacle generally contains either the same orhigher number of optical fibers compared to the connector. Since theconnector has only two optical fibers in aperture numbers 7 and 11, theonly optical fibers that will be used in the receptacle are opticalfibers in aperture numbers 7 and 11. Other optical fibers in thereceptacle (in aperture numbers 2, 3, 13, and 14) are not be utilizedsince there are no corresponding optical fibers in the connector.

For each type of sensor probe, a connector has metal pins occupyingdifferent apertures in the connector. For example, in FIG. 7A, theconnector has metal pins occupying aperture numbers 6 and 10(represented by double circles). The metal pins are electricallyconnected by a wire loop as shown in FIG. 6A. When an identifier circuitin the console sends an electrical signal to each aperture in thereceptacle and determines that there is a short circuit conditionbetween aperture numbers 6 and 10, then the identifier circuit can senda signal to a processor, identifying a type of sensor probe that isattached to the receptacle.

FIG. 8A shows a cross-sectional view of a connector 800 of anothersensor probe. In the embodiment shown in FIG. 8A, four apertures(aperture numbers 3, 7, 11, and 14) of the connector are filled withoptical fibers, rather than two apertures as shown in FIG. 7A. Theconnector shown in FIG. 8A is typically used with a sensor probe withfour sensor openings in its oximeter sensor unit.

FIG. 8B shows a cross-sectional view of a receptacle 850 which isconfigured to mate with connector 800 of a sensor probe shown in FIG.8A. The receptacles shown in FIGS. 7B and 8B are identical. Typically, asingle receptacle is attached or affixed to the console, and the samereceptacle is used for inserting a number of different sensor probes.Thus, the receptacle may have the same or higher number of opticalfibers than connectors of sensor probes. Depending on the number ofoptical fibers present in the connector, there may be extra opticalfibers in the receptacle that do not have complementary optical fibersin the connector.

In another aspect, embodiments of the invention include an adapter whichcan be used to convert a conventional receptacle (i.e., without ablocking cylinder) which is affixed to a console into a receptacle witha new design (i.e., with a blocking cylinder).

FIG. 9A illustrates a longitudinal sectional view of an adapter 900 thatincludes a female connector member 901 at one end of the adapter, and amale receptacle member 903 at the opposite end of the connector member.The female connector member of the adapter can be attached to theconventional receptacle which is affixed to the console. Then, the malereceptacle member of the adapter can be used to connect a sensor probewith a connector in accordance with the present invention.

Female connector member 901 of the adapter has substantially sameelements as a connector of a sensor probe shown in FIG. 4B. For example,the female connector member has a housing 920 with multiple apertures921 that run along the longitudinal axis of the housing. In FIG. 9A, oneof the apertures has an optical fiber 907. The female connector memberalso has a collar 925 around the housing. The collar assists in stablyconnecting and securing the connector of a sensor probe to thereceptacle mounted on the console.

Male receptacle member 903 of the adapter also has substantially sameelements as the receptacle shown in FIG. 5B. The male receptacle memberhas multiple apertures 931. One or more apertures can be filled opticalfibers 907. The male receptacle member also has a blocking cylinderwhich is inserted into one of the apertures. The blocking cylinder hasappropriate dimensions so it can fit into a cylinder receiving aperturein the connector of a sensor probe.

In one implementation, the female connector member and the malereceptacle member of the adapter can be functionally connected togetherby a cable 905 as shown in FIG. 9A. The cable can have one or moreoptical fibers which run uninterruptedly from apertures of a receptaclemember to apertures of a connector member of the adapter. For example,optical fiber 907 has one terminal end in receptacle member 903 and theother terminal end in connector member 901.

In another implementation, a connector member and a receptacle member ofan adapter can be adjoined together in a single housing enclosure,rather than being connected by a cable. For example, cable 905 shown inFIG. 9A can be omitted, and a proximal end 913 of the receptacle membercan be adjoined to and integral with a proximal end 915 of the connectormember of the adapter to form an adapter in a single housing enclosure.It may be desirable to use an adapter in a single housing rather than anadapter with a cable, if it is not necessary to extend the overalllength of a sensor probe.

FIG. 9B illustrates a longitudinal sectional view of another adapter 950that includes a female connector member 951 at one end of the adapter,and a male receptacle member 903 at the opposite end of the connectormember. The female connector member of the adapter can be attached to areceptacle on the console which has features shown in FIGS. 5A and 5B.The male receptacle member of the adapter can be connected a connectorof a sensor probe shown in FIGS. 4A and 4B. The adapter shown in FIG. 9Bcan be used to extend the overall length of a cable between a consoleand an oximeter sensor.

The elements shown in FIG. 9B are substantially same as the elementsshown in FIG. 9A, except for an aperture 961 in the female connectormember of the adapter. Aperture 961 has a top portion which has a largerdiameter than the rest of the aperture or other apertures. Aperture 961is configured to receive a blocking cylinder head on a receptaclemounted on a console.

In one implementation, the female connector member and the malereceptacle member of adapter 950 can be functionally connected togetherby a cable. In another implementation, a connector member and areceptacle member of an adapter can be adjoined together in a singlehousing, rather than being connected by a cable, if it is not necessaryto extend the overall length of a sensor probe.

While the connector and receptacle are shown to be used with a sensorprobe with a small patch oximeter sensor unit shown in FIGS. 3 and 6A,the connectors and receptacles in accordance with the present inventioncan be used to connect any type of sensor probes to a console. Forexample, a sensor probe can be a cerebral sensor probe which measuresoxygen saturation of brain tissue. Details of a cerebral sensor probeare discussed in U.S. patent application Ser. No. 12/116,013 filed May6, 2008, which is incorporated by reference.

In another example, a sensor probe can be a spot probe or pen probewhich measures oxygen saturation of a small tissue area. A spot probe orpen probe is shown and discussed in FIG. 14 of U.S. patent applicationSer. No. 12/178,359 filed Jul. 23, 2008, which is incorporated byreference.

In yet another example, a sensor probe can be a thenar sensor probewhich measures oxygen saturation of thenar area in the thumb. Details ofa thenar sensor probe are discussed in U.S. patent application Ser. No.12/110,994 filed Apr. 28, 2008, which is incorporated by reference.

In some embodiments, the connector and receptacle in accordance with thepresent invention can be used with sensor probes that have an additionalfunction other than measuring oxygen saturation of a tissue. Forexample, a sensor probe can be a surgical elevator sensor probe whichcan elevate and manipulate a tissue and measure oxygen saturation of thetissue. Details of a surgical elevator sensor probe are discussed inU.S. patent application Ser. No. 12/194,508 filed May 19, 2008, which isincorporated by reference.

An example of a surgical elevator sensor probe is shown in FIG. 10. Asurgical elevator has an oximeter sensor at its tip, which allowsmeasuring of oxygen saturation of a tissue. Surgical elevators play animportant role in medicine. Depending on the surgical procedure,elevators may be used to measure, elevate, manipulate, or cut. One areaof medicine in which surgical elevators are typically used is duringspinal surgery.

FIG. 10 shows a perspective view of a surgical elevator 1005. Thesurgical elevator includes a handle 1010, connected to a shaft 1015,connected to a tip 1020. A cable 1025 exits at a proximal end 1030 ofthe handle. The handle may be at least partially enclosed by a handlejacket 1035. The shaft may be at least partially enclosed by a shaftjacket 1040. The tip includes a first blade portion 1050 that isconnected to a second blade portion 1052 at a connection 1053. In aspecific embodiment, the first blade portion includes two openingsincluding openings 1055 and 1060 which function as an oximeter sensor.

Another example of a sensor probe that has a dual function is a tissueretractor sensor probe. A tissue retractor sensor probe can retract atissue, such as a nerve, in addition to measuring oxygen saturation ofthe tissue at the point of contact. Details of a tissue retractor sensorprobe are discussed in U.S. patent application Ser. No. 12/126,860,filed May 24, 2008, which is incorporated by reference.

FIG. 11 shows an implementation of a system 1150 which includes amonitoring console 1103 and a nerve retractor sensor probe 1155. In thisimplementation, the nerve retractor sensor probe which has an additionalfunction (i.e., retracting a nerve) in addition to measuring oxygensaturation of the nerve at the point of contact.

As shown in FIG. 11, a nerve retractor sensor probe 1155 includes aretractor that has a handle 1156, a shaft 1166 connected at its proximalend 1167 to the first handle, and a tip 1172 connected to a distal end1168 of the shaft. The shaft can be made of steel. The tip includes aretractor portion or retractor blade 1188 and an oximeter sensor 1185.Oximeter sensor 1185 has one or more sensor openings 1189 on a bottomsurface of the oximeter sensor, adjacent to retractor blade 1188.

The shaft can include an internal channel or passageway. Optical fiberscan pass from sensor openings on the tip, through the channel, throughthe handle, and into a cable jacket or cable insulation. Alternatively,the fibers can be run along the shaft and secured by, for example,shrink wrap. The optical fibers that travel inside or along the shaftare exposed through sensor opening 1189 on a bottom surface of tip 1172.Cable 1115 that includes optical fibers, and terminal ends of theoptical fibers are inside connector 1120. The connector aligns terminiof these optical fibers with termini of optical fibers present inreceptacle 1125 which is attached to system unit or console 1103.

FIG. 12 shows a perspective view of a first implementation of a tip1205. The tip includes a retractor blade and an oximeter sensor 1210attached to a top surface 1215 of the tip. The tip attaches to a shaft1220. The tip also includes a retractor portion 1223. Optical fibers areencased in a cable jacket 1225, travel along the shaft, into theoximeter sensor, and are exposed through an opening on a bottom surface1230 of the tip. Cable jacket 1225 and shaft are wrapped with a tubing1235. Such tubing may be heat-shrink tubing.

In a specific implementation of FIG. 12, the tip of the retractor has alength of about 17.5 millimeters, width of about 8 millimeters, and athickness (not including the retractor blade) of about 5 millimeters.

FIG. 13 shows a bottom view of the first implementation of a tip 1305.The tip has a retractor blade and slot 1310, within which there aresensor openings. There are four sensor openings for ends of fiber opticcables. The openings 1315 a, 1315 b, 1320 a, and 1320 b are for sourceand detector fibers.

Since the tip shown in FIG. 13 has four optical fibers, the connectorshown in FIG. 8A can be used. As described above, the connector shown inFIG. 8A provides four conductors (e.g., optical fibers) inside fourapertures of the connector. These conductors are aligned with theconductors shown in FIG. 8B.

FIG. 14 shows a perspective view of a second implementation of a tip1405 with an encasement 1410 which contains optical fiber attached tothe tip.

In a specific implementation of FIG. 14, the tip of the retractor has alength of about 17.5 millimeters, width of about 8 millimeters, and athickness (not including the retractor blade) of about 3 millimeters.

FIG. 15 shows a bottom view of the second implementation of a tip 1505.The tip includes a retractor blade and four sensor openings on a bottomsurface 1510 of the tip. The sensor openings include openings 1515 a,1515 b, 1515 c, and 1515 d. Optical fiber is connected to each of thesensor openings. The sensor openings can include sources and detectors.

FIG. 16 shows a perspective view of a third implementation of a tip1605.

FIG. 17 shows a bottom view of the third implementation of a tip 1705.The tip includes two sensor openings on a bottom surface 1710 of thetip. The two sensor openings include an opening 1715 and an opening1720. The openings include a source and detector.

Since the tip shown in FIG. 17 has two optical fibers, the connectorshown in FIG. 7A can be used. As described above, the connector shown inFIG. 7A provides two conductors (e.g., optical fibers) inside fourapertures of the connector. These conductors are aligned with theconductors shown in FIG. 7B.

This description of the invention has been presented for the purposes ofillustration and description. It is not intended to be exhaustive or tolimit the invention to the precise form described, and manymodifications and variations are possible in light of the teachingabove. The embodiments were chosen and described in order to bestexplain the principles of the invention and its practical applications.This description will enable others skilled in the art to best utilizeand practice the invention in various embodiments and with variousmodifications as are suited to a particular use. The scope of theinvention is defined by the following claims.

The invention claimed is:
 1. A method comprising: providing a firstoptical conductor having a first distal end and a first proximal end;providing a second optical conductor having a second distal end and asecond proximal end; and the first and second optical conductors arecoupled to a sensor probe comprising: a handle, comprising an axis; anda blade, coupled to the handle, comprising a first blade portion and asecond blade portion, wherein the second blade portion is between thefirst blade portion and the handle, the first blade portion is angled bya first angle relative to the handle's axis, a first side of the firstblade portion faces toward the handle, and a second side of the firstblade portion faces away from the handle, the second side of the firstblade portion comprises a first sensor structure and a second sensorstructure, where the first and second sensor structures will face tissueto be measured, the first optical conductor is coupled to the firstsensor structure, and the second optical conductor is coupled to thesecond sensor structure.
 2. The method of claim 1 wherein ends of thefirst and second optical conductors terminate at the first and secondsensor structures.
 3. The method of claim 1 comprising: providing aconnector, coupled to the first and second conductors, wherein the firstand second optical conductors terminate at the connector.
 4. A methodcomprising: providing a first conductor having a first distal end and afirst proximal end; providing a second conductor having a second distalend and a second proximal end; and the first and second conductors arecoupled to a sensor probe comprising: a handle, comprising an axis; anda blade, coupled to the handle, comprising a first blade portion and asecond blade portion, wherein the second blade portion is between thefirst blade portion and the handle, the first blade portion is angled bya first angle relative to the handle's axis, a first side of the firstblade portion faces toward the handle, and a second side of the firstblade portion faces away from the handle, the second side of the firstblade portion comprises a first sensor structure and a second sensorstructure, where the first and second sensor structures will face tissueto be measured, the first conductor is coupled to the first sensorstructure, the second conductor is coupled to the second sensorstructure, and the first and second conductors comprise optical fibers.5. The method of claim 1 wherein the first sensor structure is used toemit light into tissue to be measured, and the second sensor structureis used to receive light that is in response to the light emitted fromthe first sensor structure.
 6. The method of claim 1 wherein the sensorprobe is a tissue oximeter.
 7. The method of claim 1 wherein the firstsensor structure is used to emit light having a wavelength in a rangefrom about 600 nanometers to about 900 nanometers.
 8. The method ofclaim 1 comprising: from the first sensor structure, emitting light intothe tissue to be measured; at the second sensor structure, receivinglight from the tissue that is in response to the emitted light from thefirst sensor structure; and based on the emitted light and receivedlight, determining an oxygen saturation for the tissue.
 9. The method ofclaim 8 comprising: providing a visual indication of the determinedoxygen saturation on a display.
 10. A method comprising: providing afirst conductor having a first distal end and a first proximal end;providing a second conductor having a second distal end and a secondproximal end; and the first and second conductors are coupled to asensor probe comprising: a handle, comprising an axis; and a blade,coupled to the handle, comprising a first blade portion and a secondblade portion, wherein the second blade portion is between the firstblade portion and the handle, the first blade portion is angled by afirst angle relative to the handle's axis, the second blade portion isangled by a second angle relative to the first blade portion, where thesecond angle is different from the first angle, the first blade portioncomprises a first side and a second side, the second side of the firstblade portion comprises a first sensor structure and a second sensorstructure, where the first and second sensor structures will face tissueto be measured, the first conductor is coupled to the first sensorstructure, and the second conductor is coupled to the second sensorstructure.
 11. The method of claim 10 wherein ends of the first andsecond conductors terminate at the first and second sensor structures.12. The method of claim 10 comprising: providing a connector, coupled tothe first and second conductors, wherein the first and second conductorsterminate at the connector.
 13. The method of claim 10 wherein the firstside of the first blade portion faces toward the handle, and the secondside of the first blade portion faces away from the handle.
 14. Themethod of claim 10 wherein the first and second conductors compriseoptical fibers.
 15. The method of claim 10 wherein the first sensorstructure is used to emit light into tissue to be measured, and thesecond sensor structure is used to receive light that is in response tothe light emitted from the first sensor structure.
 16. The method ofclaim 10 wherein the sensor probe is a tissue oximeter.
 17. The methodof claim 10 wherein the first sensor structure is used to emit lighthaving a wavelength in a range from about 600 nanometers to about 900nanometers.
 18. The method of claim 10 comprising: from the first sensorstructure, emitting light into the tissue to be measured; at the secondsensor structure, receiving light from the tissue that is in response tothe emitted light from the first sensor structure; and based on theemitted light and received light, determining an oxygen saturation forthe tissue.
 19. The method of claim 18 comprising: providing a visualindication of the determined oxygen saturation on a display.
 20. Themethod of claim 10 wherein the first angle and second angle are inopposite rotation directions.